Lesson Overview: In this activity, students use a physical model to learn how the vertical arrangement of fuels affects the potential for fires to spread into tree crowns. This activity applies mainly to forests, shrublands, and woodlands. It is especially relevant to ponderosa pine/Douglas-fir forests in the northern Rocky Mountains and North Cascades, where surface fires have been excluded for nearly a century.

Lesson Goal: Increase students’ understanding of the relationship between fuel arrangement and vertical fire spread, especially in forests, shrublands, and woodlands.

Objectives:

• Students can design a model tree that can keep a surface fire from spreading into the crown.
• Students can differentiate between forest stands based on the spatial arrangement of fuels.
• Students can describe the kinds of fuels that contribute to surface fires and crown fires.